a-a a-b a-c aaa aab aac aag aak aan aao ab- aba abb abc abg abk abn abo ac- aca acb acc acg ack acn aco ag- aga agb agc agg agk agn ago aka akb akc akg akk akn ako an- ana anb anc ang ank ann ano aoa aob aoc aog aok aon aoo baa bab bac bag bak ban bao bba bbb bbc bbg bbk bbn bbo bca bcb bcc bcg bck bcn bco bga bgb bgc bgg bgk bgn bgo bka bkb bkc bkg bkk bkn bko bna bnb bnc bng bnk bnn bno boa bob boc bog bok bon boo c-- caa cab cac cag cak can cao cba cbb cbc cbg cbk cbn cbo cca ccb ccc ccg cck ccn cco cga cgb cgc cgg cgn cgo cka ckb ckc cko cn- cna cnb cnc cng cnn cno co- coa cob coc cog cok con coo gaa gab gac gag gak gan gao gba gbc gbg gbk gbn gbo gca gcb gcc gcg gck gcn gco gga ggb ggc ggg ggn ggo gka gkb gkn gko gna gnb gnc gnn gno goa gob goc gog gok gon goo ka- kaa kab kac kag kak kan kao kba kbb kbc kbk kbn kbo kca kcb kcc kcg kck kcn kga kgb kgc kgo kkb kkc kkk kkn kn- kna knc kng knk knn kno koa kob koc kog kok kon koo naa nab nac nag nak nan nao nba nbb nbc nbg nbk nbn nbo nca ncb ncc ncg nck ncn nco nga ngb ngc ngg ngk ngn ngo nka nkc nkk nkn nko nna nnb nnc nng nnk nnn nno no- noa nob noc nog nok non noo oaa oab oac oag oak oan oao ob- oba obb obc obg obk obn obo oc- oca ocb occ ocg ock ocn oco oga ogc ogg ogn ogo oka okb okc okg okk oko on- ona onb onc ong onk onn ono oo- ooa oob ooc oog ook oon ooo